Flow Reversing Device

ABSTRACT

An external support that routes the tubing of a reversing valve in such a manner that connection tubes extend from one end of the device and the treatment device tubes extend from the opposite end. The external support may provide guides that hold the tubing extending from the supported flat rotary switch type of valve so as to keep them from being pinch or kinked thereby ensuring free flow of blood.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application claims the benefit of U.S. Provisional Application No.62/478,518 filed Mar. 29, 2017, which is incorporated herein byreference in its entirety.

BACKGROUND

Hemodialysis and other forms of extracorporeal blood treatment requirethe removal of blood from a patient by means of an arterial set, passingof the blood to a blood processing device such as a dialyzer, andreturning of the blood to the patient again through a venous blood set.

Maintenance of a good blood set access is a major cost of dialysis,which is the most common extracorporeal blood treatment, although othertypes of blood treatment are also used, for example passing of the bloodthrough an absorption bed for removal of toxins and the like,hemoperfusion, and other forms of blood treatment.

Beyond the initial cost of the surgical procedure to establish a fistulaor graft in the patient, the keeping of adequate blood flow in anarterialized vein or synthetic arteriovenous graft of the patientfrequently involves secondary surgical intervention for reconstructionof an old blood vessel site on the patient. Alternatively, it may benecessary to establish an entirely new fistula or graft at a new site ifthe old one fails.

Failure is evidenced typically by stenosis of the blood vessel, orblockage of an implanted catheter or other venous access site, with aconsequent reduction in blood flow that eventually shuts down the site.Clotting is also a major cause of reduced blood flow.

If site failure is detected early enough, a less invasive technique suchas balloon angioplasty can be employed to open the stenosis at a greatlyreduced cost. Early detection of stenosis can be measured by change inpressure in the blood vessel or implant that reflects a restrictionbeginning to form. The technique described in Omachi U.S. Pat. No.5,454,374 has been used to measure the baseline pressure access site forearly detection of such a pressure change. Another method used byclinicians is to measure recirculation in the vessel during dialysis. Asthe flow is restricted in the access, the blood pumping rate indicatedon the dialysis machine may exceed the flow rate of fresh blood cominginto the vessel, so that some is recirculated from the venous accesssite to the arterial access site in the patient. This leads toinadequate dialysis since already cleansed blood is thus beingreprocessed.

Various methods for measuring the degree of recirculation of this typeare known. Another method described by Krivitsky determines blood flowin the access as a marker for stenosis. In this method blood set flowand recirculation are compared between arterial and venous flow in thenormal orientation, and then with reversed flow between the arterial andvenous access sites, which are typically fistula needles which enter thevein. In the prior art, clinicians typically accomplish this by stoppingthe flow of blood, clamping off all the lines, disconnecting the set orsets from the fistula needles, and then reconnecting the arterial lineto the venous fistula while connecting the venous line to the arterialfistula.

Also regarding catheters (which are typically connected to larger veinsor even the vena cava) it is known that catheter blockage may berelieved by reversing flow.

Catheters which are implanted in the venous system of a patient fordialysis access or the like may develop a “fibrin sheath” on the outsideof the catheter within the blood vessel, for example the jugular orsubclavian veins or the vena cava. This fibrin sheath coats the outsideof the catheter and can extend over the end thereof.

At the outflow port, such a fibrin sheath is generally not too serious aproblem since the outflowing blood forces the fibrin sheath open easily.However, at the inflow port of the catheter, the sheath can act as aone-way valve, collapsing with increasing negative pressure to seriouslyinterfere with flow through the catheter.

Upon such an occurrence, a blood flow reversing valve may reverse theflow of blood through the catheter for continuation of a desired medicalprocedure such as hemodialysis application.

Referring to FIGS. 1A through 1E, a number of alternative designs forfour-way valves have been developed for blood circuits. Referring toFIG. 1A, U.S. Pat. No. 5,894,011, discloses a valve that swaps theconnections between pairs of lines 905 and 906 via a pair of rotatablyconnected disks 901 and 902, each of which supports one of the pairs oflines 905 and 906. The latter reference, for purposes of the USdesignation in the current PCT application, is hereby incorporated byreference in its entirety herein. A seal must be maintained between thedisks 901 and 902 and between the respective lines. The device isintended to be operated manually. The parts are required to be rotated180 degrees and must be rotated to a full lock before the seal and fullpatency are provided. Also, any indication of the two positions, such asa pointer and label, cannot be placed in a single location so that theposition of the valve is indicated by looking at it. For example, if apointer is positioned on the bottom and rotated 180 degrees from aforward to the reverse position, the pointer cannot be seen from oneside as with the configuration of a valve like the quarter-turn typevalve of U.S. Pat. No. 4,885,087 discussed below.

Referring to FIG. 1B, another four-way valve, disclosed in U.S. Pat. No.5,605,630, which has been proposed for use in blood lines, has arotating wheel 910 with channels 911 and 912 defined between the wheel910 and the inside of a housing 913. The latter reference, for purposesof the US designation in the current PCT application, is herebyincorporated by reference in its entirety herein. When the wheel isrotated, the channels 911 and 912 shift to join a different pair oflines. This device also has seals.

Referring to FIG. 1C, another arrangement is proposed in U.S. Pat. No.6,177,049, which for purposes of the US designation in the current PCTapplication, is hereby incorporated by reference in its entirety herein.This device has a rotating component 915 with channels 921 and 922defined within it. As the rotating component 915 is rotated, thechannels defined between pairs of lines 917 and 919 change from parallellines joining one set of corresponding lines to U-shaped channelsjoining a different set.

Referring to FIGS. 1D and 1E, a design, disclosed in U.S. Pat. No.4,885,087, for purposes of the US designation in the current PCTapplication, hereby incorporated by reference in its entirety herein, isvery similar to that of FIG. 1B. This design has a rotator 925 thatconnects different pairs of lines depending on the position therebydefining two different sets of possible flow channels 926 and 929 or 927and 931.

Referring to FIG. 1E, another type of four-way valve is formed byinterconnecting two tubes 937 and 938 with crossover lines 935 and 936.This design is disclosed in U.S. Pat. No. 6,189,388 (Hereafter, “U.S.Pat. No. '388”), which for purposes of the US designation in the currentPCT application, is hereby incorporated by reference in its entiretyherein. Tube pinching actuators 941-944 are used to force fluid throughdifferent channels, depending on which actuators are closed. This deviceprovides a hermetic seal and can be fairly inexpensive, but in a givenconfiguration, significant no-flow areas are defined. These dead spacescan lead to the coagulation of blood, which is undesirable. Also, theinterconnection of tubes in this does not lend itself to automatedmanufacturing.

Another type of four-way valve is based on the generally configurationof FIGS. 1H through 1L except that it is motor-actuated. A pinchingmechanism achieves selection of opposite loop branches to switch flowpaths by rotating a cam in the middle of the loop. The displacement ofthe cam can be less than 90 degrees between the two stop positions. Thisconfiguration is described in U.S. Pat. No. 8,002,727, which forpurposes of the US designation in the current PCT application, is herebyincorporated by reference in its entirety herein.

Solutions known in the prior art include U.S. Pat. No. 6,177,049, for“Reversing Flow Blood Processing System,” which discloses a bloodprocessing system having a reverse flow valve therein so that flowthrough the arterial and venous fistulas, or other equivalent patientconnection equipment, can be reversed without reversing or stopping theblood pump. Another solution known in the prior art is U.S. Pat. No.6,319,465 for “Reversing flow blood processing system having reducedclotting potential.” Referring to FIG. 1G, another type of flowreversing valve of simple construction is shown by U.S. Pat. No.4,885,087 for “Apparatus for mass transfer involvingbiological/pharmaceutical media.” The valve described by the latterdisclosure is of simple construction and is very intuitive and easy fora user to change the flow direction by rotating a lever. The generaldesign of a lever and a cross-shaped set of tubes follows a manualreversing valve design used in plumbing systems as shown in the figurebelow.

Another very simple and inexpensive design uses a loop 204 from whichfour tubes 205 stem. The loop 204 can be made up of 4 T-shaped junctionsfitted together so that the four tubes 205 extending radially from it. Adouble tube-pinching clamp 202, is shown in side and top views at 202Aand 202B respectively. The double tube-pinching clamp 202 is positionedas shown in FIG. 1K to reverse (as shown in FIG. 1L) the flow betweenpairs of tubes. Although this configuration has a low cost ofmanufacture, some users may find it difficult to understand completelycreating a training burden and concomitant risk. It will be observedthat the routing of the tubes to make side-by-side sets ofcountercurrent flows is not apparent from the way the tubes stem fromthe loop 204.

One feature of many of the prior art configuration is that they havetubes coming out of the flow switch that cross, when a first pair oftubes is extended toward the patient and a second pair of tubes isextended toward the treatment device. This can form a confusingarrangement. Although U.S. Pat. No. 6,319,465 does not have thisdrawbackthe blood tubes extending to the patient extend from the sameside and the blood tubes extending to the treatment device extend froman opposite side the configuration is complex and expensive tomanufacture and can be unintuitive to use.

SUMMARY

The drawbacks of the prior art are overcome by providing a flat rotaryswitch type of valve as described in U.S. Pat. No. 4,885,087 without thedrawbacks identified above and with additional benefits as hereindescribed. First, the problem of crossing blood lines is resolved byproviding an external support that routes the tubing in such a mannerthat the patient connection tubes extend from one end of the device andthe treatment device tubes extend from the opposite end. The externalsupport may provide guides that hold the tubing extending from thesupported flat rotary switch type of valve so as to keep them from beingpinch or kinked thereby ensuring free flow of blood. The flow switch issupported by the external support which can also support indiciaindicating the switch position. The external support can include anenclosure. The enclosure may be of an ergonomic design that fitscomfortably in the hand. In embodiments, the ergonomic design isasymmetrical to provide an indication or orientation.

Objects and advantages of embodiments of the disclosed subject matterwill become apparent from the following description when considered inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments will hereinafter be described in detail below with referenceto the accompanying drawings, wherein like reference numerals representlike elements. The accompanying drawings have not necessarily been drawnto scale. Where applicable, some features may not be illustrated toassist in the description of underlying features.

FIGS. 1A-1H and 1J-1L illustrate various flow reversing devicesaccording to the prior art.

FIG. 2 illustrates a flow circuit including a blood treatment machineand a reversing valve, according to embodiments of the disclosed subjectmatter.

FIGS. 3A through 3E show a reversing valve and various features thereof,according to embodiments of the disclosed subject matter.

FIGS. 4A through 4D show a reversing valve device according toembodiments of the disclosed subject matter.

FIGS. 5A and 5B show a 3D printable version of a reversing valve withsmooth channels embedded in a valve body to provide mutually adjacentpairs of counter current ports on the valve body, according toembodiments of the disclosed subject matter.

FIGS. 6A through 6D show an embodiment of a support for routing tubes toachieve many of the technical functions described with regard to otherembodiments in a compact form and without a full enclosure, according toembodiments of the disclosed subject matter.

FIGS. 7A and 7B shows an embodiment of a support that provides routingof tubes from opposite sides of the four-way valve without enclosing oreven being directly connected to the four-way valve, according toembodiments of the disclosed subject matter.

FIGS. 8A and 8B show a cam-type actuator actuating a loop type flowreversal device as shown in the embodiment of FIGS. 1H and 1J through 1Lwhich allows a four way valve to be formed without any seals, mayprovide an angular displacement of less than 90 degrees, and whichemploys a détente mechanism to lock the rotating cam, according toembodiments of the disclosed subject matter.

FIGS. 9A and 9B show a cam-type actuator actuating a loop type flowreversal device as shown in the embodiment of FIGS. 1H and 1J through 1Lwhich allows a four way valve to be formed without any seals, mayprovide an angular displacement of less than 90 degrees, and whichpermits over-rotation of the internal cam and the resilience of theoutside cams to provide the function of a détente mechanism without anadditional component, according to embodiments of the disclosed subjectmatter.

DETAILED DESCRIPTION

Referring now to FIG. 2, a patient 130 is connected by an access 139 toa blood processing machine 315. The latter draws blood through anarterial blood line 305 and returns treated blood to the patient 130through a venous blood line 307. The blood processing machine 315 may beany treatment device such as a hemodialysis machine, a hemofiltrationmachine, an infusion pump (in which case no arterial line 305 would bepresent), etc.

Access 139 may consist of various devices such as a fistula (not shown)and catheter (not shown) combination or other type of access which maybe disconnected by various means. For example, a catheter (not shown)may be withdrawn from a fistula (not shown) and/or the catheter (notshown) disconnected from the arterial 307 and venous 305 lines by meansof a luer connector (not shown). The above are conventional features ofwhich a variety of alternatives are known.

A reversing valve 311 causes the arterial line at the patient end toswitch places selectively with the venous line and the patient end. Thiscauses the blood to flow in an opposite direction at the patient end;through the patient access.

Referring to FIGS. 3A, 3B, and 3C, a reversing valve 380 (also called a4-way valve) is shown in section. The reversing valve 380 has a rotatingelement 382 with channels 386 within a port block 388. The rotatingelement 382 forms a seal with the port block 388. The port blockprovides ports 384 for attachment of tubes. Tubes may be bonded bywelding or by adhesive. The valve operates according to the sameprinciples as prior art embodiments disclosed above. FIGS. 3A, 3B, and3C show the rotating element 382 in a first position, an intermediatetransition position, and a second position respectively. The first andsecond positions provide parallel and reverse flow respectively. FIG. 3Dshows a perspective view of the reversing valve 380. The details of theembodiment of FIGS. 3A through 3D are a mere example of a configurationsuitable for manufacturing of biocompatible materials. Other shapes ofthe elements are known in the prior art and may readily be devised basedon the basic principles herein disclosed. As will be more evident afterthe discussion of the embodiments of FIGS. 4A through 4D, the featuresof the reversing valve 380 that are particularly relevant to thedisclosed subject matter include the following.

-   -   1. The angular displacement from a side of the reversing valve        380. That is the axis of rotation is provided on a flexible face        of the reversing valve 380, unlike the prior art configuration        FIG. 1A where tubes are aligned with the axis of rotation. That        is, the tubes stem from the valve parallel to the axis and        therefor do not allow the attachment of an actuation element        such as a handle 388 to switch the valve.    -   2. The magnitude of rotation required to switch the valve is        less than 180 degrees and preferably about 90 degrees. This        makes it more convenient to switch.    -   3. As illustrated in FIG. 3E, the configuration is such that for        use in configuration where the valve is to be applied in an        application that establishes counter-current parallel flow paths        indicated at 395 that extend away from the valve in opposite        directions, the tubing 385 connected to the valve 380 must cross        390 as shown in FIG. 3E.

Referring now to FIG. 4A a reversing valve device 400 has a housing 440with a flow switch handle 401. The flow switch handle is connected to areversing valve within the housing that has the 3 features enumeratedabove. The enclosure 440 has openings 406 that permit tubes to extendaway from the reversing valve device 400 in pairs in opposite directionsor on opposite sides of the reversing valve device 400. Referring toFIGS. 4B and 4C, which show the inside of the reversing valve device400. To provide the configuration where respective pairs of inflow andoutflow tubes extend from opposite sides of the house, the housing 440is provided with guides that guide tubes in a fashion that holds thecrossing tubes in the housing. In this way the device can provide aclean appearance and an easy-to-hold shape as shown in FIG. 4D.

A first pair of counter-current tubes 409 and 410 are connected onopposites side of the reversing valve 380. A second, different, pair ofcounter-current tubes 407 and 408 are also connected on differentopposites side of the reversing valve 380. The tubes 408 and 410 areheld in a crossing arrangement. In the present embodiment, the tubes aresupported in channels that help to ensure there are no kinks in thetubes despite the tortuous path followed by tubes 408 and 410. Thearrangement can be open of fully enclosed by a housing. Other types ofsupports can provide a similar effect. It will be evident that theenclosure can be formed from two separate halves each of which can bemolded in a simple single-shot two-part mold. It will also be evidentthat the enclosure 440 can have a variety of shapes. Various differenthandles for activating the valve may be provided. The drawings show around knurled knob 422 and a blade-shaped handle 423 as examples. FIG.4D shows another view similar to the view of FIG. 4A.

FIGS. 5A and 58 shows a 3D printable version of a reversing valve withsmooth channels embedded in a valve body to provide mutually adjacentpairs of counter current ports on the valve body. A valve body 510 maybe 3D printed to define channels 506 that cross and channels 508 that donot cross. The valve body 510 may be formed to seal with a stopcock 502that provides the reversing valve function. It will be evident byinspection that the reversing valve function is provided and thatmutually adjacent pairs of counter current ports on the valve body canprovide counter current flow from and to a remote device. The featuresof this device are as described in connection with the foregoingembodiments except separate tubes and a separate enclosure are notrequired.

FIGS. 6A through 6D show an embodiment of a support for routing tubes toachieve many of the technical functions described with regard to otherembodiments in a compact form and without a full enclosure, according toembodiments of the disclosed subject matter. FIG. 6A shows a four-wayvalve device 381 which may have many specific details, but in thisinstance is depicted as one similar in configuration and functionallythe same as the embodiment of FIGS. 3A through 3E. In the presentembodiment, the four-way valve has an actuator 516 with a pointer 520.Tubes 515A, 5158, 517A, 5178 stem from a reversing valve 380 in radialdirections and such a first pair 515A and 5158 that attach to one deviceare located opposite each other and second pair 515A and 5158 thatattach to another device are located opposite each other, assuming theflow switch is used for changing a flow direction between two devicessuch as a source and return of fluid being one device and a consumerreceiver and return being another. Here again, to allow the pairs to bearranged to help make it evident which tubes attach to each device,tubes 5158 and 5178 are crossed. A support 520 partially encloses thecrossing tubes 5158 and 5178 and attaches to the four-way valve 380 bycapturing it with pins (not shown) that fit into locator holes 518 inthe four-way valve 380. Indicia similar to those described above withreference to FIG. 4A may be provided on the support 520. The finalconfiguration is shown in FIG. 6D. It will be evident from inspectionthat the tubes are held in a configuration in which pairs are formedbetween tubes are arranged in pairs with one pair 515A and 5158 arrangedso that it is evident that it attaches to one device located oppositethe second pair 515A and 515B that attach to another device. Thearrangement makes the attachments apparent by pairing the tubes thatconnect to one device, that is, placing them close to each other thanthe tubes that connect to the other device. The arrangement also makesthe attachments apparent by placing the tubes that connect to one deviceopposite those that connect to the other device. These features, it willbe observed, are as in other embodiments described herein.

FIGS. 7A and 7B show an embodiment of a support that provides routing oftubes from opposite sides of the four-way valve without enclosing oreven being directly connected to the four-way valve, according toembodiments of the disclosed subject matter. The arrangement is the sameas the flow-switch 381 of FIG. 6A except that the actuator has indicia540 and 541 directly on it and there are no locator holes 518. A sleeve522 is positioned over the crossing tubes 515B and 517B. The sleeve 525may be a flexible of any suitable construction for example a metalspring, a textile piece with a Velcro closure, or a springy element(plastic, metal) that snaps over the tubes and holds them to a shapeconforming to its shape such the curved shape shown. Other arrangementssuch as even wire ties will be readily apparent from the disclosure.

FIGS. 8A and 8B show a cam-type actuator actuating a loop type flowreversal device as shown in the embodiment of FIGS. 1H and 1J through 1Lwhich allows a four-way valve to be formed without any seals, mayprovide an angular displacement of less than 90 degrees, and whichemploys a détente mechanism to lock the rotating cam, according toembodiments of the disclosed subject matter. A support 240 has bosses232 arrayed around a perimeter thereof and projecting inwardly to pincha tubing loop 204 as described with reference to FIGS. 1H and 1J through1L. The fame 240 has a pivoting cam element 230 that rotates to pinch anopposing pair of legs of the loop 204 in each position. FIG. 8A showsthe cam element 230 in one position whereby a flow may be established ina forward direction and FIG. 8B shows the cam element 230 in a secondposition whereby a flow may be established in a reverse direction. Notethat throughout the disclosure the distinction between forward andreverse may exist at a system level so the designations may be arbitraryfor purposes of the present disclosure of the flow switching deviceapart from a connected system. A détente mechanism including a pin 232urged toward a cam 231 maintains the position of the cam element 230 oneach of the forward and reverse positions. The pin may be urged by aspring or other device suitable for causing the device to operate as adétente mechanism. A handle may be provided for actuating the camelement 230 manually. A handle is not shown but the form and means foraffixing one to the cam element should be evident from general knowledgeand the disclosure. It will be apparent by inspection that the range ofmotion of the cam element 230 between the forward and reverse détentepositions is less than 90 degrees. Also, it should be apparent that theloop 204 should be formed of a flexible material to permit it to bedeformed as illustrated. Further, the cm element 230 may have a slipperysurface so that it does not overly distort the loop 204 when it moves.For example the cam element 230 may have a fluorocarbon coating or itmay have small rollers.

FIGS. 9A and 9B show a cam-type actuator actuating a loop type flowreversal device as shown in the embodiment of FIGS. 1H and 1J through 1Lwhich allows a four way valve to be formed without any seals, mayprovide an angular displacement of less than 90 degrees, and whichpermits over-rotation of the internal cam and the resilience of theoutside bosses to provide the function of a détente mechanism without anadditional component, according to embodiments of the disclosed subjectmatter. Instead of providing a separate détente mechanism, stops (notshown) permit the cam element 230 to rotate past the positions of arespective the bosses 232 to compress the walls of the tubing of whichthe legs are formed and/or resiliently bend the bosses 232 therebylocking the tips of the cam element 230 behind the bosses 232 andlocking the cam element in a corresponding forward or reverse position.

According to embodiments, the disclosed subject matter includes a flowreversing device. A flow reversing valve is of a type that switches byangular displacement of an actuator element thereof that is accessiblefrom a side thereof, there being no ports or tubes extending from saidside. The flow reversing valve provides full reversal with less than 180degrees of rotation. Two pairs of tubes extend from respective oppositesides of the flow reversing valve. A support holds the flow reversingvalve and tubes extending away therefrom such that each pair of tubesemerges from the support on opposites sides of the support.

In variation, the support encloses the flow reversing valve and crossingportions of two of the tubes. In further variations, the supportencloses the flow reversing valve and crossing portions of two of thetubes, the two of the tubes belonging to different ones of said pairs.

In still further variations, the support encloses the flow reversingvalve and crossing portions of two of the tubes forming an enclosure,the enclosure being kidney-shaped.

In yet more variation, the flow reversing valve has an actuator handlethat is asymmetric and functions as a pointer to indicia on the supportindicating forward and reversed positions of the flow reversing valve.

According to further embodiments, the disclosed subject matter includesa flow reversing device. A flow reversing valve is of a type thatswitches by angular displacement of an actuator element thereof that isaccessible from a side thereof, there being no ports or tubes extendingfrom said side. The flow reversing valve provides full reversal withless than 180 degrees of rotation. In embodiments, the reversal happenswith about 90 degrees of rotation. Two pairs of tubes extend fromrespective opposite sides of the flow reversing valve. A support holdsthe flow reversing valve and tubes such that they extend away therefromand such that each pair of tubes emerges from the support mutuallyadjacent positions.

In variations of the further embodiments, the support encloses the flowreversing valve and crossing portions of two of the tubes. In furthervariations of the further embodiments, the support encloses the flowreversing valve and crossing portions of two of the tubes, the two ofthe tubes belonging to different ones of said pairs. In variations ofthe further embodiments, the support encloses the flow reversing valveand crossing portions of two of the tubes forming an enclosure, theenclosure being kidney-shaped. In variations of the further embodiments,the flow reversing valve has an actuator handle that is asymmetric andfunctions as a pointer to indicia on the support indicating forward andreversed positions of the flow reversing valve.

According to still more embodiments, the disclosed subject matterincludes a flow reversing device with a flow reversing valve of a typethat switches by angular displacement of an actuator element thereofthat is accessible from a side thereof, there being no ports or tubesextending from the side. The flow reversing valve provides full reversalwith less than 180 degrees of rotation. There are two pairs of tubes,the members of each pair originating and extending from respectiveopposite sides of the flow reversing valve. A support holds the flowreversing valve and tubes extending away therefrom such that each pairof tubes emerges from the support on opposites sides of the support. Invariations of any embodiment, the support encloses the flow reversingvalve and crossing portions of two of the tubes. In variations of anyembodiment, the support encloses the flow reversing valve and crossingportions of two of the tubes, the two of the tubes belonging todifferent ones of the pairs. In variations of any embodiment the supportencloses the flow reversing valve and crossing portions of two of thetubes forming an enclosure. In variations of any embodiment the supportholds two of the tubes such that they cross each other with each of thetwo forming one of each of the two pairs. In variations of anyembodiment the support has indicia indicates forward and reverse flowdirections and the flow reversing valve has an actuator handle that isasymmetric and functions as a pointer to indicia on the supportindicates forward and reversed positions of the flow reversing valve. Invariations of any embodiment the support has indicia indicates forwardand reverse flow directions and the flow reversing valve has an actuatorhandle that is asymmetric and functions as a pointer to indicia on thesupport indicates forward and reversed positions of the flow reversingvalve, the support, defining an enclosure, having multiple externalmajor faces and the indicia being on a same one of the external faces.In variations of any embodiment the flow reversing valve provides fullreversal with no more than 90 degrees of rotation.

According to still more embodiments, the disclosed subject matterincludes a flow reversing device. In the device, a flow reversing valveis of a type that switches by angular displacement of an actuatorelement thereof that is accessible from a side thereof, there being noports or tubes extending from the side. The flow reversing valveprovides full reversal with less than 180 degrees of rotation. There aretwo pairs of tubes, the members of each pair extending from respectiveopposite sides of the flow reversing valve. A support holds the flowreversing valve and tubes extending away therefrom such that each pairof tubes emerges from the support adjacent each other.

In variations of any embodiment the support encloses the flow reversingvalve and crossing portions of two of the tubes. In variations of anyembodiment the support encloses the flow reversing valve and crossingportions of two of the tubes, the two of the tubes belonging todifferent ones of the pairs. In variations of any embodiment the supportencloses the flow reversing valve and crossing portions of two of thetubes forming an enclosure. In variations of any embodiment the supportholds two of the tubes such that they cross each other with each of thetwo forming one of each of the two pairs. In variations of anyembodiment the support has indicia indicates forward and reverse flowdirections and the flow reversing valve has an actuator handle that isasymmetric and functions as a pointer to indicia on the supportindicates forward and reversed positions of the flow reversing valve. Invariations of any embodiment the support has indicia indicates forwardand reverse flow directions and the flow reversing valve has an actuatorhandle that is asymmetric and functions as a pointer to indicia on thesupport indicates forward and reversed positions of the flow reversingvalve, the support, defining an enclosure, having multiple externalmajor faces and the indicia being on a same one of the external faces.In variations of any embodiment the flow reversing valve provides fullreversal with no more than 90 degrees of rotation.

According to still further embodiments, the disclosed subject matterincludes a flow reversing device in which a valve body has four portsand a rotating stopcock having multiple channels therein. The four portsand the multiple channels are arranged to provide a flow reversing valvefunction when the stopcock is rotated by an angular displacement of lessthan 180 degrees. An actuator element on a side of the stopcock isaccessible from a side of the valve body, there being no ports facingthe side. The four ports form first ends of channels within the valvebody with second ends opening to an external face of the valve body.There are two pairs of the second ends, each pair being mutuallyadjacent on the external face with each pair connecting to respectivemembers of the other pair in both positions of the rotating stopcock. Invariations of any embodiment the two of the channels cross are spacedapart along an axis of rotation of the stopcock to permit them to crosseach other to opposite sides of the valve body. In variations of anyembodiment the stopcock has an actuator handle that is asymmetric andfunctions as a pointer to indicia on the valve body. In variations ofany embodiment the valve body is 3D-printed.

According to yet more embodiments, the disclosed subject matter includesa flow reversing device with a flow reversing valve of a type thatswitches by angular displacement of an actuator element thereof that isaccessible from a side thereof, there being no ports or tubes extendingfrom the side. The flow reversing valve provides full reversal with lessthan 180 degrees of rotation. There are two pairs of tubes, the membersof each pair originating and extending from respective opposite sides ofthe flow reversing valve. In variations of any embodiment a supportholds the flow reversing valve and tubes extending away therefrom suchthat the tubes of each pair are mutually adjacent. In variations of anyembodiment the support holds the pairs of tubes such that they arelocated on opposites sides of the support. In variations of anyembodiment the support holds the tubes such that one of each pair isparallel or collinear with one of the other pair. In variations of anyembodiment the support encloses the flow reversing valve and crossingportions of two of the tubes. In variations of any embodiment thesupport encloses the flow reversing valve and crossing portions of twoof the tubes, the two of the tubes belonging to different ones of thepairs. In variations of any embodiment the support encloses the flowreversing valve and crossing portions of two of the tubes forming anenclosure, the enclosure being kidney-shaped. In variations of anyembodiment the flow reversing valve has an actuator handle that isasymmetric and functions as a pointer to indicia on the supportindicates forward and reversed positions of the flow reversing valve.

According to yet embodiment, the disclosed subject matter includesmethod of routing four tubes from a four-way valve in which tubes extendfrom a flow switch in four directions, two of which directions areorthogonal to the other two directions. The method includes routing afirst of the four tubes to position it adjacent to a second of the fourtubes stemming from a side of the flow switch opposite a side of theflow switch from which the first of the four tubes stems. The methodfurther includes routing a third of the four tubes to position itadjacent to a fourth of the four tubes stemming from a side of the flowswitch opposite a side of the flow switch from which the third of thefour tubes stems. The method further includes fixing the four tubes in aposition resulting from the first and second routings. In variations ofany embodiment the fixing includes at least partially enclosing the flowswitch. In variations of any embodiment the method includes providingaccess to an actuator of the flow switch by means of a handle residingat least partially outside an enclosure resulting from the at leastpartially enclosing.

In variations, the methods may include indicating a position of the flowswitch actuator by aiming a pointer of the handle at a respectiveindicium on the enclosure. The first and second routings may cause thefirst and third tubes to cross each other. Each of the four tubes maystem from the flow switch initially at 90 degrees from two nearestneighboring ones of the four tubes. In variations of any embodiment thetwo of the four tubes a curved such that each stems from an enclosureresulting from the enclosing at 45 degrees from an angle at which itstems from the flow switch. In variations of any embodiment the two ofthe four tubes a curved such that each stems from an enclosure resultingfrom the enclosing at 135 degrees from an angle at which it stems fromthe flow switch. In variations of any embodiment the flow switch has twostop positions corresponding to forward and reverse flow configurationsand the pointer of the handle points to the first and second tubes whenthe handle is positioned in one stop position and to the third andfourth tubes when handle is positioned in the other stop position. Invariations of any embodiment the flow switch has two stop positionscorresponding to forward and reverse flow configurations and the twostop positions are affected by an angular displacement of the handlethat is no more than 90 degrees.

According to still further embodiments, the disclosed subject matterincludes a flow switch device with a loop of tubing with four tubingbranches extending from it, the loop having two pairs of opposed tubinglegs. A support has four sides each having a boss that engages with arespective one of the tubing legs making up the two pairs. A cam elementis inside the loop. In a first rotational position, the cam elementpinches one of the two pairs of opposed tubing legs and in a secondrotational position pinches another of the two pairs of opposed tubinglegs. A détente mechanism releasably holds the cam element in each ofthe first and second rotational positions when the cam element ismanually rotated. In variations of any embodiment the détente mechanismincludes a pin urged toward a cam with a recess for receiving the pin.In variations of any embodiment the détente mechanism includes stopsthat allow the cam element to rotate a predefined position beyond aposition of the bosses so as to releasably trap the cam element in aselected position. In variations of any embodiment a retaining elementholds two of the tubing branches 1 and 3 in a crossing relation suchthat each of tubing branches 1 and 3 is positioned closer to arespective one of two others 2 and 4 than to each other (i.e., tubingbranches 1 and 3 are more remote from each other than tubing branches 1and 2 or tubing branches 3 and 4), thereby forming two paired adjacenttubing branches: pair 1=tubing branches 1 and 2 and pair 2=tubingbranches 3 and 4 and such that each pair includes one of the crossingtubing branches, the cam element defining a flow path connecting flowbranches 1 to 3 and 2 to 4 when in the first position and 1 to 4 and 2to 3 when in the second position.

According to still more embodiments, the disclosed subject matterincludes a flow switch device with a flow switch with four portsoriented at 90 degree intervals around a center of the flow switch. Theflow switch is of a type that forms selectable flow passages betweenports separated by 90 degrees and blocks flow between ports separated by180 degrees in each of multiple selected positions. Two of the ports areconnected to fixed flow passages each defining a flow path toward aremote port separated from the each by 180 degrees so that the each anda respective remote port are positioned in pairs on opposite sides ofthe flow switch. In variations of any embodiment the fixed flow passagesinclude flexible curved tubes held by a retaining device to hold them ina curved state. In variations of any embodiment the retaining deviceincludes a support that at least partially encloses the flow switch. Invariations of any embodiment the retaining device includes a supportthat fully encloses the flow switch. In variations of any embodiment theretaining device is connected to the flow switch. In variations of anyembodiment the flow switch has a manually operable actuator. Invariations of any embodiment the retainer has indicia for indicates aposition of the flow switch. In variations of any embodiment theretainer or the flow switch has indicia for indicates a position of theflow switch. In variations of any embodiment the retainer includes aflexible clip. In variations of any embodiment the retainer constitutesa flexible clip. In variations of any embodiment the each and therespective remote port have tubes extending parallel and away from theflow switch. In variations of any embodiment the each and the respectiveremote port have tubes extending parallel and in opposite directionsfrom the flow switch.

It is, thus, apparent that there is provided, in accordance with thepresent disclosure, flow reversing device. Many alternatives,modifications, and variations are enabled by the present disclosure.Features of the disclosed embodiments can be combined, rearranged,omitted, etc., within the scope of the invention to produce additionalembodiments. Furthermore, certain features may sometimes be used toadvantage without a corresponding use of other features. Accordingly,Applicants intend to embrace all such alternatives, modifications,equivalents, and variations that are within the spirit and scope of thepresent invention.

1. A flow reversing device, comprising: a flow reversing valve of a typethat switches by angular displacement of an actuator element thereofthat is accessible from a side thereof, there being no ports or tubesextending from said side; the flow reversing valve providing fullreversal with less than 180 degrees of rotation; two pairs of tubes, themembers of each pair originating and extending from respective oppositesides of the flow reversing valve; a support holding the flow reversingvalve and tubes extending away therefrom such that each pair of tubesemerges from the support on opposites sides of the support.
 2. Thedevice of claim 1, wherein the support encloses the flow reversing valveand crossing portions of two of the tubes.
 3. The device of claim 1,wherein the support encloses the flow reversing valve and crossingportions of two of the tubes, the two of the tubes belonging todifferent ones of said pairs.
 4. The device of claim 1, wherein thesupport encloses the flow reversing valve and crossing portions of twoof the tubes forming an enclosure
 5. The device of claim 1, wherein thesupport holds two of the tubes such that they cross each other with eachof the two forming one of each of the two pairs.
 6. The device of claim5, wherein the support has indicia indicating forward and reverse flowdirections and the flow reversing valve has an actuator handle that isasymmetric and functions as a pointer to indicia on the supportindicating forward and reversed positions of the flow reversing valve.7. The device of claim 4, wherein the support has indicia indicatingforward and reverse flow directions and the flow reversing valve has anactuator handle that is asymmetric and functions as a pointer to indiciaon the support indicating forward and reversed positions of the flowreversing valve, the support, defining an enclosure, having multipleexternal major faces and the indicia being on a same one of the externalfaces.
 8. The device of claim 1, wherein the flow reversing valveprovides full reversal with no more than 90 degrees of rotation.
 9. Aflow reversing device, comprising: a flow reversing valve of a type thatswitches by angular displacement of an actuator element thereof that isaccessible from a side thereof, there being no ports or tubes extendingfrom said side, the flow, reversing valve providing full reversal withless than 180 degrees of rotation; two pairs of tubes, the members ofeach pair extending from respective opposite sides of the flow reversingvalve; a support holding the flow reversing valve and tubes extendingaway therefrom such that each pair of tubes emerges from the supportadjacent each other.
 10. The device of claim 9, wherein the supportencloses the flow reversing valve and crossing portions of two of thetubes.
 11. The device of claim 9, wherein the support encloses the flowreversing valve and crossing portions of two of the tubes, the two ofthe tubes belonging to different ones of said pairs.
 12. The device ofclaim 9, wherein the support encloses the flow reversing valve andcrossing portions of two of the tubes forming an enclosure.
 13. Thedevice of claim 9, wherein the support holds two of the tubes such thatthey cross each other with each of the two forming one of each of thetyro pairs.
 14. The device of claim 9, wherein the support has indiciaindicating forward and reverse flow directions and the flow, reversingvalve has an actuator handle that is as asymmetric and functions as apointer to indicia on the support indicating forward and reversedpositions of the flow reversing valve.
 15. The device of claim 10,wherein the support has indicia indicating forward and reverse flowdirections and the flow reversing valve has an actuator handle that isasymmetric and functions as a pointer to indicia on the supportindicating forward and reversed positions of the flow reversing valve,the support, defining an enclosure, having multiple external major facesand the indicia being on a same one of the external faces.
 16. Thedevice of claim 9, wherein the flow reversing valve provides fillreversal with no more than 90 degrees of rotation.
 17. A blood flowreversing device, comprising: a valve body with four ports, a rotatingstopcock having multiple channels therein, the four ports and themultiple channels being arranged to provide a flow reversing valvefunction when the stopcock is rotated by an angular displacement of lessthan 180 degrees; an actuator element on a side of the stopcock that isaccessible from a side of the valve body, there being no ports facingsaid side; the four ports forming first ends of channels within thevalve body with second ends opening to an external face of the valvebody; there being two pairs of said second ends, each pair beingmutually adjacent on said external face with each pair connecting torespective members of the other pair in both positions of the rotatingstopcock.
 18. The device of claim 17, wherein the two of the channelscross are spaced apart along an axis of rotation of said stopcock topermit them to cross each other to opposite sides of the valve body. 19.The device of claim 18, wherein the stopcock has an actuator handle thatis asymmetric and functions as a pointer to indicia on the valve body.20. The device of claim 17, wherein the valve body is 3D-printed. 21-55.(canceled)
 56. A flow reversing device, comprising: a flow reversingvalve of a type that switches by angular displacement of an actuatorelement thereof that is accessible from a side thereof, there being noports or tubes extending from said side; the flow reversing valveproviding full reversal with less than 180 degrees of rotation, twopairs of counter-current tubes, the members of a first of said pairsoriginating and extending from opposite sides of the flow reversingvalve, and the members of a second of said pairs originating andextending from different opposite sides of the flow reversing valve, asupport holding the flow reversing valve and tubes extending awaytherefrom such that each pair of tubes emerges from the support onopposites sides of the support, wherein the support encloses the flowreversing valve and crossing portions of two of the tubes forming anenclosure, the two of the tubes belonging to different ones of saidpairs, wherein the enclosure has openings that permit the tubes toextend away from the reversing valve device in pairs in oppositedirections of the reversing valve device, and wherein the support holdsthe two of the tubes such that they cross each other with each of thetwo forming one of each of the two pairs, wherein the enclosure isprovided in its inside with guides that guide the tubes in a fashionthat holds the crossing tubes in the enclosure to thereby provide theconfiguration where the respective pairs of inflow and outflow tubesextend from opposite sides of the enclosure.
 57. The device of claim 56,wherein the support has indicia indicating forward and reverse flowdirections and the flow reversing salve has an actuator handle that isasymmetric and functions as a pointer to indicia on the supportindicating forward and reversed positions of the flow reversing valve.58. The device of claim 56, wherein the support has indicia indicatingforward and reverse flow directions and the flow reversing valve has anactuator handle that is asymmetric and functions as a pointer to indiciaon the support indicating forward and reversed positions of the flowreversing valve, the support, defining an enclosure, having multipleexternal major faces and the indicia being on a same one of the externalfaces.
 59. The device of claim 56, wherein the flow reversing valveprovides full reversal with no more than 90 degrees of rotation.